Inflatable life jackets due to their ability to quickly place strong buoyant moments where needed about the body of an unconscious Man Over Board (“MOB”) are usually able to provide superior corrective turning performance relative to inherently buoyant Personal Flotation Devices (“PFDs”). The foam life jacket if shaped identical to an inflatable life jacket may also provide superior performance. However the shape of an inflatable life jacket is acceptable in that it is water activated or manually activated only in an emergency. Once in the throes of a water emergency the large anterior displacement is no longer a compliance issue. Until inflated the stored inflatable PFD is low profile and consequently comfortable to wear until needed.
The foam PFD while considerably cheaper than an inflatable PFD, compromises performance for comfort. When the foam PFD is worn routinely, an anterior foam block sufficiently large to provide airway protective corrective turning can be so bulky as to be incompatible with either vocation or avocation. As the amount of foam increases from the 15 lbs. provided by many Type III to the 24 lbs. of the Type II to the 35 lbs. of a Type I, comfort and compliance falls off rapidly. The Type I Off shore PFD being can be so oppressive that it typically never worn until after the onset of a marine accident. The recreational boater is strongly encouraged to “Boat Smart From The Start” meaning to wear your life jacket not carry it. Continuous use has led to the popularizing or the Type III boaters vest which has little to no corrective turning capacity.
Over six hundred boaters drown a year attributed in large part to their failure to wear a life jacket or PFD at the time of the accident. While law requires boaters to carry one PFD for each person on board a vessel, in an emergency PFDs become stuck beneath an over turned vessel, beneath the seat or in the lazaret where stowed. If the PFD is found they are very hard to don while floating in water. Fifty per cent of the 65 fatalities that occur each year while wearing a life jacket are attributed to PFDs incorrectly donned or adjusted. The practice of water donning is understood to be so difficult that it currently is not assessed during the USCG/UL PFD approval process.
Compared to foam PFDs inflatable PFDs are very comfortable leading to increased compliance with continual use. However, this clear advantage is only available at a cost, a cost so high as to be prohibitive for many family boaters. The inflatable PFD purchase price and maintenance cost are directly proportional to the size of the CO2 cylinder. The 16 gm CO2 that generates approximately 16 pounds of displacement, costs approximately a dollar because the 16 gm cylinder is produced in mass quantities for many uses. However available 16 gm PFDs usually do not provide sufficient torque to protect the airway. Current life jackets employ inflators which operate by piercing the compressed gas cylinder releasing the gas which then expands. There is a linear relationship between the number of grams of CO2 attached to current life jacket inflators and the pounds of inflatable displacement that can be generated from that CO2.
Cylinders other than the 16 gram CO2 are very expensive; a 24-gram costs around $12.00 retail and a 38-gram $18.00. New 1F inflator adds onto the prior cost the additional costs of a custom 38 gram cylinder and a custom plastic marking device that is broken off during installation so that the cylinder can not be installed a second time. This is to assure that a spent cylinder is not re-installed during re-arming. This technology is so new that the cost for this assurance of cylinder seal integrity has yet to be determined but predictably it will exceed the current $18.00 per cylinder.
Due to the prohibitive cost of compressed gas inflation, all USCG Type I to V PFDs have a single inflator and a single compressed gas cylinder. While Safety Of Life At Sea (“SOLAS”) class inflatable Life Jackets do require dual inflators and cylinders, the cost of SOLAS class life jackets restricts their use to profitable commercial carriers.
Studies have shown that inflatable life jackets after being in the field for 6 months suffer a 50% loss of reliability. Spent cylinders are reinstalled or cylinders vibrate away from the piercing means so that neither manual nor water activated inflators are capable of inflating the attached PFD. While recent 1F inflators address some of the issues the increased cost will only further restrict the high performance of inflatable life jackets to those with significant financial resources.
There are no known triple chambered PFD systems. Additionally, the retail cost of including a component could end up being approximately four times the wholesale cost. At a wholesale cost of $9.00/38 gm CO2 the customer could end up paying $36.00. Thus, using current 38-gram cylinders for a triple chambered PFD could add $100.00 to the final purchase price. The new modified 38 gm cylinders required for the 1F would add even more the purchase price. The wholesale price for the 1F inflator can be $12.00 which could add $48.00 to the retail price for each inflator. Three inflators could contribute $147.00 to the retail cost. The combined retail cost of the inflators and cylinders for a triple chambered PFD thus could be $250.00 plus the additional costs for the custom cylinder and collar. This price does not include the cost of the radio frequency welded jacket, sewn cover, harness and required pamphlet.
In addition to the costs of inflating a triple chambered PFD, the inclusion of three cylinders and three inflators adds considerable bulk and weight to a garment integrated PFD, adversely affecting compliance with ‘continuous use’.
Current compressed gas inflation systems which are restricted to expansion of compressed gas have restricted the design of life jackets to single chambered products. Clearly the compressed gas inflation means required to inflate the personal life raft has blocked it from consideration for routine inclusion in PFDs or garments.
While certain large multi-person life rafts and buoyant Airline slides have self-orienting buoyant aspirators. These single use commercial aspirators are sized to the device to be inflated and rely upon bulky self-orienting collars which are required to assure that the bladder will not be filled with entrained seawater rather than entrained air. They are very large, heavy, bulky and expensive devices incompatible for inflation of continuously worn life jackets yet alone for the inflation of single-use disposable Mylar life jacket or signaling devices.
Current CO2 inflators approved for use with UL/USCG Tested & Approved inflatable life jackets rely upon manual or water activated rapid discharge of the cylinders entire contents into the air retentive bladder. The amount of displacement generated is in direct proportion to the weight of liquid CO2 in the cylinder. Classically inflatable life jackets rely upon a 16 gm, 25 gm or 38 gram CO2 cylinders generating roughly 1 lb displacement/gm during direct rapid high-pressure inflation.
Current life jacket inflators are required to roll the victim from a face down position into an airway protected face up position in 5 seconds. Design objectives of current UL listed inflators are to rapidly pierce the cylinder seal then reduce obstruction to gas flow. In one design the rapid and complete transfer of gas if facilitated by inverted mounting of the cylinder so that the liquid CO2 is blown into the chamber where it can rapidly expand with the ambient pressure sustained by the constriction of the cylinder walls. For the unconscious victim this rapid clearing of the airway is essential and that remains the default operational mode of the disclosed inflator.
Over and above USCG Type III, II Near Shore or Type I Offshore PFDs, SOLAS class inflatable life jackets as dictated by the International Maritime Organization (“IMO”) are required to have redundant chambers, cylinder and inflators to mitigate the possibility that failure at one point could lead to complete loss of all buoyant assistance. In one design both chambers share a common wall. One of the two chambers is protected by an over pressure valve so in the event both the manual and automatic inflators are activated, the entire contents of one cylinder/chamber is safely spilled out through the over pressure valve. In dual inflator life jackets the second is only present as a back up and yet through volume amplification could be used to inflate the life raft, mitigating hypothermic risk, markedly extending survival.
Thus there remains the need for a user oriented therefore low bulk, low cost, low profile, and lightweight volume amplifying life jacket CO2 inflator to which the present invention is directed.